HighCVE-2026-46113

Linux Kernel: Use-After-Free (CVE-2026-46113)

Published 28.05.2026Last modified 19.10.2026Sources: SUSE, Debian LTS, BSI, Ubuntu, Siemens ProductCERT, Red Hat, CVE.org, EUVD, Msrc Update Guide

What is affected, what to do

Update Linux Kernel to version 5.15.222, Linux Kernel to version 6.1.175, Linux Kernel to version 6.6.140.

Affected: Linux Kernel lt 2.6.20..5.15.222
Linux Kernel lt 5.16..6.1.175
Linux Kernel lt 6.2..6.6.140
Linux Kernel lt 6.7..6.12.88
Linux Kernel lt 6.13..6.18.30
Linux Kernel lt 6.19..7.0.7
Fixed in: Linux Kernel 5.15.222
Linux Kernel 6.1.175
Linux Kernel 6.6.140
Linux Kernel 6.12.88
Linux Kernel 6.18.30
Linux Kernel 7.0.7
Linux Kernel 7.1

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Metrics

8.8

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v3

8.8

CVSS v3

Severity High on the scale from 0 to 10.

Source: SUSE, Debian LTS, BSI, Ubuntu, Siemens ProductCERT, Red Hat, CVE.org, EUVD, Msrc Update Guide

0.2 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 9.2

Show all metrics

Severity: High
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 62.73 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 8.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 8.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.2 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 9.2; Low — this CVE sits in the lower 10% of all CVEs scored today.
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 28.05.2026
CISA assessment (SSVC): Exploitation: none known · not automatable · Technical impact: total; Source: CISA Vulnrichment, as of 16 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-416

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Fix shadow paging use-after-free due to unexpected GFN

The shadow MMU computes GFNs for direct shadow pages using sp->gfn plus the SPTE index. This assumption breaks for shadow paging if the guest page tables are modified between VM entries (similar to commit aad885e77496, "KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE", 2026-03-27). The flow is as follows:

a PDE is installed for a 2MB mapping, and a page in that area is accessed. KVM creates a kvm_mmu_page consisting of 512 4KB pages; the kvm_mmu_page is marked by FNAME(fetch) as direct-mapped because the guest's mapping is a huge page (and thus contiguous).
the PDE mapping is changed from outside the guest.
the guest accesses another page in the same 2MB area. KVM installs a new leaf SPTE and rmap entry; the SPTE uses the "correct" GFN (i.e. based on the new mapping, as changed in the previous step) but that GFN is outside of the [sp->gfn, sp->gfn + 511] range; therefore the rmap entry cannot be found and removed when the kvm_mmu_page is zapped.
the memslot that covers the first 2MB mapping is deleted, and the kvm_mmu_page for the now-invalid GPA is zapped. However, rmap_remove() only looks at the [sp->gfn, sp->gfn + 511] range established in step 1, and fails to find the rmap entry that was recorded by step 3.
any operation that causes an rmap walk for the same page accessed by step 3 then walks a stale rmap and dereferences a freed kvm_mmu_page. This includes dirty logging or MMU notifier invalidations (e.g., from MADV_DONTNEED).

The underlying issue is that KVM's walking of shadow PTEs assumes that if a SPTE is present when KVM wants to install a non-leaf SPTE, then the existing kvm_mmu_page must be for the correct gfn. Because the only way for the gfn to be wrong is if KVM messed up and failed to zap a SPTE... which shouldn't happen, but actually only happens in response to a guest write.

That bug dates back literally forever, as even the first version of KVM assumes that the GFN matches and walks into the "wrong" shadow page. However, that was only an imprecision until 2032a93d66fa ("KVM: MMU: Don't allocate gfns page for direct mmu pages") came along.

Fix it by checking for a target gfn mismatch and zapping the existing SPTE. That way the old SP and rmap entries are gone, KVM installs the rmap in the right location, and everyone is happy.

Source: suse_csaf, Debian LTS Advisories, BSI WID Portal, BSI CSAF, Ubuntu Security Notices, siemens_advisory, redhat_csaf, cvelistv5, ENISA EUVD, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE)

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
Linux	Linux	`5.16 – < 6.1.175` `6.7 – < 6.12.88` `6.2 – < 6.6.140` `2.6.20 – < 5.15.222` `6.19 – < 7.0.7` `—` `6.13 – < 6.18.30`	`6.1.175` `6.12.88` `6.6.140` `5.15.222` `7.0.7` `7.1` `6.18.30`
IBM	QRadar SIEM	`<7.5.0 UP15 IF06`	—
Siemens	SIMATIC S7	`1500 TM MFP V1.1.1 GNU/Linux subsystem`	—

Vendors and products

Affected operating systems

Affected operating systems

Linux	debian	linux	`bookworm`
Linux	debian	linux-6.1	`bullseye`
Linux	linux	linux_kernel	`7.1`
Linux	linux	linux_kernel	—

Weakness classes (CWE)

CWE-416Use After Free
Variant
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Entry at MITRE CWE-416

References & sources

git.kernel.orgstable/c/488e386484ec8c0e558be6e156edf34ed9f4d5c8euvd, Patch
git.kernel.orgstable/c/06c19c967b845b63172601fe459667d973b7e6b7euvd, Patch
git.kernel.orgstable/c/738ec97b1855df6c08fe2369f798fa0b972e556beuvd, Patch
git.kernel.orgstable/c/14d1e55dfd2cf4711bff164a6aaaddb783552134euvd, Patch
git.kernel.orgstable/c/0cb2af2ea66ad8ff195c156ea690f11216285bdfeuvd, Patch
git.kernel.orgstable/c/e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0Patch
git.kernel.orgstable/c/9597963a8ca16259d194a1d9950d7bd22a10ab2f
Siemens ProductCERTproductcert/html/ssa-784472.html

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

19.10.2026Record modifiedCISA ADP
Weakness type: CWE-416
Show the original change
Individual changes of this event as published by NVD
Type Action Before After
Weakness type (CWE) added
—
CWE-416
Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Individual changes of this event as published by NVD
Type	Action	Before	After
Weakness type (CWE)	added	—	CWE-416

16.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: no

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-46113","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:19:45.859135Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

15.10.2026Record modifiedSiemens ADP

New references:

https://cert-portal.siemens.com/productcert/html/ssa-784472.html

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46113.json">CVE-2026-46113</a>
Reference	added	—	https://cert-portal.siemens.com/productcert/html/ssa-784472.html

Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

03.10.2026Record modifiedLinux

New references:

and 3 more references

Show 20 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46113.json">CVE-2026-46113</a>
Reference	added	—	https://git.kernel.org/stable/c/06c19c967b845b63172601fe459667d973b7e6b7
Reference	added	—	https://git.kernel.org/stable/c/0cb2af2ea66ad8ff195c156ea690f11216285bdf
Reference	added	—	https://git.kernel.org/stable/c/14d1e55dfd2cf4711bff164a6aaaddb783552134
Reference	added	—	https://git.kernel.org/stable/c/488e386484ec8c0e558be6e156edf34ed9f4d5c8
Reference	added	—	https://git.kernel.org/stable/c/738ec97b1855df6c08fe2369f798fa0b972e556b
Reference	added	—	https://git.kernel.org/stable/c/9597963a8ca16259d194a1d9950d7bd22a10ab2f
Reference	added	—	https://git.kernel.org/stable/c/e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0
Reference	removed	https://git.kernel.org/stable/c/06c19c967b845b63172601fe459667d973b7e6b7	—
Reference	removed	https://git.kernel.org/stable/c/0cb2af2ea66ad8ff195c156ea690f11216285bdf	—
Reference	removed	https://git.kernel.org/stable/c/14d1e55dfd2cf4711bff164a6aaaddb783552134	—
Reference	removed	https://git.kernel.org/stable/c/488e386484ec8c0e558be6e156edf34ed9f4d5c8	—
Reference	removed	https://git.kernel.org/stable/c/738ec97b1855df6c08fe2369f798fa0b972e556b	—
Reference	removed	https://git.kernel.org/stable/c/e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0	—
Reference type	removed	https://git.kernel.org/stable/c/06c19c967b845b63172601fe459667d973b7e6b7 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/0cb2af2ea66ad8ff195c156ea690f11216285bdf Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/14d1e55dfd2cf4711bff164a6aaaddb783552134 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/488e386484ec8c0e558be6e156edf34ed9f4d5c8 Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/738ec97b1855df6c08fe2369f798fa0b972e556b Types: Patch	—
Reference type	removed	https://git.kernel.org/stable/c/e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0 Types: Patch	—

Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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<a href="https://intel.neosec.eu/en/cve/CVE-2026-46113"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-46113.svg?lang=en" alt="CVE-2026-46113 – NEOSEC Intel" height="20"></a>